1. Technical Field
The present invention relates to a data processing device, and particularly, to a data processing device having a data storage section storing data.
2. Related Art
Image data picked up by an image pick-up device such as a digital camera can be stored in various memory cards inserted into the image pick-up device. Although the capacity of such memory cards is increasing, there still exists a problem that a capacity of the memory card can become used up during use thereof when being used an image pick-up device having a high number of pixels or when a moving image is being picked up, whereby image pick-up cannot be further continued. To solve the problem, a portable storage device has appeared so as to meet a desire for ensuring a capacity used for newly picked up image data in the memory card by taking a back-up of the image data from the memory card during image pick-up outdoors. The storage device is smaller and lighter than a personal computer. The storage device is fast in starting up and easy to operate.
However, since various kinds of data are stored in the storage device, it is necessary to ensure security of the stored data. Input of authentication information such as a password may be required of users at the time of starting up the storage device so as to ensure the security of the data.
A method of requiring input of authentication information such as a password at the time of starting up is widely used as a measure for preventing unauthorized access of a personal computer (for example, see JP-A-2005-293282). However, when the method is applied to a data processing device such as the above-mentioned storage device, input of the authentication information is necessary even at the time of backing up the data stored in the memory card in the data processing device, thereby causing the user trouble. In other words, since the portable storage device is powered by a battery, power is normally turned off when the device is not in use and the power is turned on only when the portable storage device is being used.
However, when the input of the authentication information is required at the time of starting up the storage device, a start-up speed, which is one of the features thereof, decreases, thereby decreasing user convenience. In particular, when the user backs up the data stored in the memory card in the data processing device, the user may want to pick up new images using the memory card as soon as possible by making the memory card empty as soon as possible.
Meanwhile, when a data security measure for a data processing device such as the storage device is not taken at all, the data is not generally encrypted. Accordingly, when the data processing device is lost or stolen, the data may be undesirably read by third parties.